The brain-independent, autonomic neuroendocrine system of insects (coelopulse). Karel Sláma, Institute of Entomology, Czech Academy of Sciences, Prague, Czech Republic.

In the late 1970´s, a brain-independent, parasympathetic-like, cholinergic nervous system was discovered in insects with the centers located in the thoracic ganglia of the ventral nerve cord. The nerve impulses were dispatched into the abdominal, intersegmental or dorsoventral muscles. The rhythmic contractions of these muscles, periodically repeated in several min intervals, produced special extracardiac pulsations in hemocoelic pressure, which were actively involved in the homeostatic regulation of some vital physiological functions: a) respiratory gas exchange through individual spiracles; b) water balance and isoosmosis by economy over the respiratory water loss; c) control of mechanical pressure within the hemocoele; and d) circulation of hemolymph through the appendages and body regions that were too far to be reached by the heartbeat. Principal components of this autonomic nervous system of insects (coelopulse) include: a) proprioceptive neurons and interneurons located within the thoracic ganglia; b) metameric system of the perisympathetic neurohemal organs containing aminergic (H-organ in the prothoracic region) or peptidergic (abdominal segments) neurosecretions; and c) extensive somatic or visceral effector musculature. Essential morphological and functional features of the coelupulse system of insects and ticks will be outlined.